It's not easy. Its absolutely crap. They are big enough to know what they are missing, but too young to have all the social media to keep in touch with their friends.
What will school be doing regarding lessons? Is any of that interactive?
I'd be contacting any friends parents you can and setting up virtual stuff - any games you can play over the screen (I'm thinking bingo, battleships, not roblox or minecraft), or craft sets they could both do simultaneously whilst chatting. Would any of her old friends do that?
My oldest is older, but on his third set of isolation since September (10 days because that's how long it took to get a negative test, and now second lot of close contact). It's been MUCH better with more structured school work. He is also doing stuff round d the house - made biscuits with DH was working from home and his brother and I were at school. Can you give her more control of something?
Are you saying it wont last for ever, and platitudes, or are you acknowledging that is crap, you hate it too, you dont know when it's over, but asking how could we make it the least bad possible? I'd be trying the opposite of whatever you've been doing til now.
I wouldnt do it right now, but for future events, when I told the kids we were going to see my parents for the 2 days before Xmas (need to be home with DH on the 25th!), I prefaced it with it was what we hoped to do, and it was all dependant on no isolation or illness of government changes. So it's something we are hoping to do, not a definite promise. We've also talked about what sweets we should get Grandpa for Christmas, because if we have to unwrap the presents over Skype as we havnt collected them, we'd also have to eat them! So something tiny but positive about the shitte show that might come.
I know the above wont suit many families, but if what you've been doing so far hasnt been getting through to her, maybe a complete change in tactic couod work?
If she is serious about the she'd rather be dead, rather than it being a dramatic statement, I'd also contact school and see what counselling they have available.